Standard Deviation Of All RR Intervals Research Articles

The Influence of Perceived Discrimination on Heart Rate Variability in Young Black Adults

Introduction: Cardiovascular disease (CVD) is the leading cause of death in the United States, with a disproportional precedence in Black adults. Heart rate variability (HRV) is used to help predict future CVD, with lower HRV indicative of a compromised cardiovascular system. Prior evidence has suggested that experienced racial discrimination is associated with CVD risk. However, there is limited information regarding experienced racial discrimination on HRV in young Black adults. Purpose/hypothesis: The purpose of this study was to determine whether personal-level and group-level racial discrimination was associated with worse HRV in young Black adults. Methods: Black adults aged 18-25 (n=18, 44.45% female) volunteered to participate in this study, arriving at the lab at 7am in a fasted state. Following 30 minutes of rest, HRV measures were assessed using a SphygmoCor 3-lead ECG in a supine position. The HRV measure included the standard deviation of all R-R intervals (SDNN), the mean number of times an hour successive NN intervals exceeds 50ms (pNN50), the root mean square of successive differences (RMSSD), the low-frequency (LF) power domain, high-frequency (HF) power domain, and their ratio (LF:HF). Participants were given a perceived racial discrimination questionnaire that assessed personal-level and group-level discrimination. Pearson correlations were used to analyze the association between perceived racial discrimination measures and HRV measures. Results: In Black males, perceived personal-level racial discrimination was negatively associated with sympathetic activity (LF, R2 = -0.704, p = 0.023) and sympathovagal balance (LF:HF, R2 = -0.749, p = 0.013), and positively associated with parasympathetic activity (HF, R2 = 0.704, p = 0.023). Perceived group-level racial discrimination was not associated with HRV measures. Furthermore, perceived racial discrimination was not associated with HRV in Black females. Conclusion: Although decreased HRV has been associated with increased risk for CVD, higher HRV has been shown to be associated with left ventricular mass in Black adults. Therefore, HRV implications may be dependent on social determinants of health and other covariates that are associated with race/ethnicity. In the current study, higher HRV was observed in Black males who reported higher personal-level discrimination, which may be an important factor in sympathetic and parasympathetic cardiac control and CVD risk. Given our preliminary findings, more research is warranted that investigates the impact of racial identity, resiliency, coping, and healthy lifestyle behaviors on mitigating the detrimental impact of perceived racial discrimination on the cardiovascular health of young Black adults. Summer Undergraduate Research Fellowship Recipient from the American Physiological Society. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Is excessive ventricular irregularity predictive of rehospitalization in patients with permanent AF and HFpEF?

There are currently limited therapeutic approaches for patients with heart failure with preserved ejection fraction (HFpEF) who have developed permanent atrial fibrillation (AF). We aimed to analyse the impact of ventricular irregularity on heart failure rehospitalization in patients with permanent AF and HFpEF. All 24h ambulatory Holter monitoring performed in our centre within a month after a first heart failure hospitalization were screened. Patients with HFpEF and permanent AF were included in the retrospective analysis. The following parameters of ventricular irregularity were calculated over the 24h recording period: standard deviation of all RR intervals (SDNN), coefficient of variation of SDNN (CV-SDNN=SDNN/mean RR), root of the mean squared differences of successive RR intervals (RMSSD), and percentage of consecutive RR intervals with difference over 50ms (pNN50). The primary endpoint was rehospitalization for acute heart failure (HFrH). From 2010 to 2021, 51/216 screened patients were included. During a median follow-up of 3.13years, 29/51 patients reached the primary endpoint. HFrH patients had higher SDNN (205±65 vs. 154±46ms; P<0.01), CV-SDNN (26±8% vs. 19±5%, P<0.01), RMSSD (182±47 vs. 138±65ms, P=0.013), and pNN50 (76±9 vs. 58±26, P<0.001) when compared with patients with no HFrH. In multivariate analysis, all those parameters remained significantly associated with HFrH. In this pilot study, we found some evidences for a deleterious impact of excessive ventricular irregularity on HFrH in AF patients with HFpEF. Those new findings could pave the way for new prognosis and therapeutic approaches in this patients' population.

Cardiac arrhythmias, conduction system abnormalities, and autonomic tone in patients with brucellosis.

Arrhythmias can occur because of cardiac involvement in patients with brucellosis. We investigated the effect of Brucella (Brucella melitensis) on cardiac arrhythmias in patients without pre-existing arrhythmogenic heart disease. 205 patients with sinus rhythm who were diagnosed with brucellosis and 205 healthy controls were enrolled. ECG was performed, and the parameters were recorded for each patient. 24-hour ambulatory ECG (Holter) monitoring was conducted, and the recordings were analyzed. The time-domain heart rate variability (HRV) results were evaluated. The average age of the group with brucellosis was 28.9±6.4 years, and 57.1% were male. The ECG parameters, including P dispersion (Pd), QT dispersion (QTd), corrected QTd (QTcd), T-peak to T-end (TpTe), and corrected TpTe (TpTec) were longer and TpTe/QT, TpTe/QTc, TpTec/QT, and TpTec/QTc ratios were higher in the study group compared to the control group (p<0.05). Holter monitoring recorded 33 (16.1%) patients in the study group and 3 (3%) in the control group with abnormal rhythms. In the brucellosis group, low frequency (LF), low/high frequency (LF/HF), and the standard deviation of all R-R intervals (SDNN) values, which are known HRV indicators, were substantially different than in the control group (p<0.001). We can evaluate the silent involvement of the cardiac conduction system in patients with brucellosis using ECG parameters, which is a non-invasive and simple method in terms of feasibility in clinical follow-up.

Conflicts hurt: Social stress modulates proinflammatory cytokines’ link with pain and sadness

Several parameters of heart rate variability (HRV) have been shown to predict the risk of sudden cardiac death (SCD) in cardiac patients. There is consensus that risk prediction is increased when measuring HRV during specific provocations such as orthostatic challenge. For the first time, we provide data on reproducibility of such a test in patients with a history of acute coronary syndrome.Sixty male patients (65 ± 8 years) with a history of acute coronary syndrome on stable medication were included. HRV was measured in supine (5 min) and standing (5 min) position on 2 occasions separated by two weeks. For risk assessment relevant time-domain [standard deviation of all R-R intervals (SDNN) and root mean squared standard differences between adjacent R-R intervals (RMSSD)], frequency domain [low-frequency power (LF), high-frequency power (HF) and LF/HF power ratio] and short-term fractal scaling component (DF1) were computed. Absolute reproducibility was assessed with the standard errors of the mean (SEM) and 95% limits of random variation, and relative reproducibility by the intraclass correlation coefficient (ICC).We found comparable SEMs and ICCs in supine position and after an orthostatic challenge test. All ICCs were good to excellent (ICCs between 0.636 and 0.869).Reproducibility of HRV parameters during orthostatic challenge is good and comparable with supine position.

Does transcatheter ventricular septal defect closure affect heart rate variability in children?

BackgroundHeart rate variability (HRV) is a sign of the cardiac autonomic nervous system. Its evaluation in pediatric ventricular septal defect (VSD) cases before and after transcatheter closure contributes to an understanding of cardiac autonomic control. MethodsNineteen children with VSDs treated with transcatheter closure and 18 healthy children were enrolled in this study. A 24-h Holter rhythm monitor was applied to all patients before VSD closure and to those in the control group. Holter rhythm monitoring was repeated at three months in the patient group. HRV parameters were measured using the Cardio Scan Premier 12® program. Frequency-domain (total power; very-low-frequency, low-frequency (LF), and high-frequency (HF) indices; and the LF/HF ratio) and time-domain (standard deviation of all RR intervals (SDNN), standard deviation of 5-min averages of RR intervals (SDANN), the SDNN index, percentage of the difference between adjacent RR intervals, and the square root of the mean of the sum of square differences between adjacent filtered RR intervals) parameters were assessed. ResultsBefore the procedure, SDNN, SDANN, and total power values were lower in the patient group than in the control group; other parameters were similar in the two groups. No significant difference in the SDNN, SDANN, or total power was detected between the patient and control groups in the third month, indicating that autonomic control of patients’ hearts became normal during the third postoperative month. No correlation was detected between any hemodynamic parameters and any time-domain or frequency-domain parameters before closure. ConclusionThis study showed that transcatheter closure of VSDs changed HRV parameters in pediatric patients.

Comparison of the autonomic nervous system dysfunction between different chronic spine disorders: neck pain versus low back pain.

SUMMARYOBJECTIVE:This study aims to compare heart rate variability (HRV) between patients with chronic neck pain and patients with chronic low back pain and to correlate the chronic pain variables with heart rate variability indices.METHODS:This is a cross-sectional study. We divided the sample into two groups: neck pain (n=30) and low back pain (n=30). We used the Numeric Pain Rating Scale, Neck Disability Index, Roland-Morris Disability Questionnaire, Pain-Related Catastrophizing Thoughts Scale, Tampa Scale of Kinesiophobia, and Pain Self-Efficacy Questionnaire. For heart rate variability analysis, we used the following indices: mean RR, standard deviation of all RR intervals, mean heart rate, root mean square differences of successive RR intervals, triangular index, triangular interpolation of the interval histogram, low-frequency band in arbitrary units and in absolute values, high-frequency band in arbitrary units and in absolute values, standard deviation of the instantaneous beat-to-beat variability (standard deviation 1), long-term standard deviation of continuous RR intervals (standard deviation 2), and Stress Index. We used Student’s t-test for comparisons and Spearman’s coefficient for correlations.RESULTS:We observe insignificant values in the differences between the groups. Disability and self-efficacy were correlated with heart rate variability only in patients with chronic neck pain, whereas catastrophizing and kinesiophobia showed greater correlations with heart rate variability in patients with chronic low back pain.CONCLUSIONS:Autonomic dysfunction of individuals with chronic neck pain, when compared to patients with chronic low back pain, does present insignificant differences.

Cardiac baroreflex sensitivity and heart rate variability are lower in humans with high affinity hemoglobin compared to typical affinity hemoglobin

BackgroundHumans with high O2 affinity hemoglobin (HAH) have a markedly lower partial pressure of O2at which 50% of hemoglobin is saturated (P50) and a leftward shift of the oxy‐hemoglobin dissociation curve. Humans with HAH have attenuated heart rate responses during both acute and chronic hypoxic exposure relative to humans with typical P50. Despite the attenuated heart rate responses to hypoxia, there are typically no blood pressure differences found in humans with HAH relative to humans with typical P50. Due to the blunted heart rate and normal blood pressure responses to hypoxia in humans with HAH, this study aimed to investigate the impact of HAH on cardiac autonomic function during normoxia and hypoxia. We hypothesized that humans with HAH would have lower cardiac baroreflex sensitivity (cBRS) and heart rate variability (HRV) during normoxia and hypoxia relative to individuals with typical P50.MethodsNine humans with a HAH mutation (6 female, Age: 40±12yrs, P50: 16±1 mmHg) and 12 controls with typical affinity hemoglobin (6 female, Age: 40±10yrs, P50: 26±1 mmHg) laid supine for 10‐minutes prior to 20‐minutes of isocapnic hypoxia, titrated to reduce arterial O2 pressure to ~50 mmHg (Avg. FiO2 = 11.9±0.0%). Beat‐to‐beat arterial pressures (arterial catheter) and heart rate (electrocardiogram) were continuously recorded. Data were averaged in five‐minute segments starting with the last five minutes of supine normoxic rest. Spontaneous cBRS was quantified using the sequence method. HRV was measured in time and frequency domains. Standard deviation of the RR interval (SDRR) was calculated as the standard deviation of all RR intervals in a data segment. Low frequency (LF) HRV was calculated using Fast Fourier Transformation and assessed as absolute spectral intensity in the LF band (0.04‐0.15Hz).ResultsArterial oxygen (PaO2) and carbon dioxide (PaCO2) pressures were not different between humans with HAH and controls during normoxia or isocapnic hypoxia [PaO2: (HAH vs. Control): 48±3 vs. 47±2 mmHg, p=0.612; PaCO2: (HAH vs. Control): 40±3 vs. 39±1 mmHg, p=0.328] exposure. cBRS was lower in humans with HAH compared to controls in normoxia and throughout isocapnic hypoxia [normoxia (HAH vs. Control): 7±4 vs. 16±10 ms/mmHg; hypoxia minutes 15‐20 (HAH vs. Control): 4±3 vs. 14±11 ms/mmHg; Hb type, p=0.024]. Several metrics of HRV were lower in humans with HAH relative to control (SDRR: Hb type, p≤0.001; LF: Hb type, p=0.030) and HRV was blunted to a similar extent in both groups with hypoxia (SDRR: time effect, p=0.009).ConclusionThe findings of this study are twofold. Compared to controls, humans with HAH have: 1) attenuated cardiac baroreflex sensitivity and 2) lower heart rate variability in both normoxia and isocapnic hypoxia.

Heart rate variability, mood and performance: a pilot study on the interrelation of these variables in amateur road cyclists.

ObjectiveThe present study seeks to explore the relationship between measures of cycling training on a given day and the heart rate variability (HRV) and mood states obtained the following morning. The association between HRV and mood state is also studied, as is the relationship between internal and external measures of training.MethodsDuring a 6-week period, five recreational road cyclists collected 123 recordings of morning HRV and morning mood, and 66 recordings of training power and rate of perceived exertion (RPE). Training power was used as an external measure of performance and RPE as an internal measure of performance. The HRV parameters used in the study were the mean of RR intervals (mean RR) and the standard deviation of all RR intervals (SDNN) as time domain analysis, and the normalized high frequency band (HFnu), normalized low frequency band (LFnu) and the ratio between low and high frequency bands, as frequency domain analysis. Mood was measured using a 10-point cognitive scale.ResultsIt was found that the higher the training power on a given day, the lower the HFnu and the higher LF/HF were on the following morning. At the same time, results showed an inverse relationship between training and mood, so the tougher a training session, the lower the mood the following day. A relationship between morning HRV and mood was also found, so that the higher mean RR and HFnu, the more positive the mood (r = 0.497 and r = 0.420 respectively; p < 0.001). Finally, RPE correlated positively with external power load variables (IF: r = 0.545; p < 0.001).ConclusionAltogether, the results indicate a relationship between training of cyclists on a given day and their morning HRV and mood state on the following day. Mood and HRV also seem positively related. It is argued that developing a monitoring system that considers external and internal training loads, together with morning mood, could help understand the state of the individual, enabling feedback to athletes to facilitate the adaptation to training and to prevent problems associated with overtraining. However, more research is needed to further understand the association between the different variables considered.

Heart rate variability, exercise capacity and levels of daily physical activity in children and adolescents with mild-to-moderate cystic fibrosis.

Background:Autonomic nervous system balance is altered in cystic fibrosis (CF), although its influence on physical fitness has been poorly explored.Objective:This study aimed to evaluate the association of heart rate variability (HRV) with exercise capacity and levels of daily physical activity in children and adolescents with mild-to-moderate CF.Methods:A cross-sectional study including individuals with CF aged 6–18 years, not under CFTR modulator therapy, was performed. Sociodemographic (age, sex) and clinical information (airway colonization, pancreatic insufficiency, and genotyping) were collected. In addition, exercise capacity (modified shuttle test — MST), lung function (spirometry), body composition (bioimpedance), levels of daily physical activity (5-day accelerometer), and HRV (both at rest and during the MST) were evaluated.Results:30 individuals (20 females) aged years, mean FEV%, were included. A sympathovagal balance (LF/HF) increase () during the MST was shown, indicating a predominance of sympathetic modulation. The standard deviation of all RR intervals (SDNN) and the high frequency (HF) index during exercise correlated significantly with FEV1 (, and , ; respectively). MST distance also correlated positively and significantly with SDNN (, ), square root of the mean of the sums of squares of frequencies between RR intervals greater than 50 ms — RMSSD (, ), low frequency — LF (, ), HF (, ), dispersion of points perpendicular to the short-term identity line — SD1 (, ) and negatively with LF/HF (, ). Regarding daily physical activity, SDNN at rest (, ) and exercise (, ) showed positive correlations with time in moderate-to-vigorous activities. When normalizing the SDNN and classifying individuals as normal or altered, those presenting altered SDNN showed poorest FEV1 () and lower exercise capacity ().Conclusion:HRV correlates with lung function, exercise capacity and levels of daily physical activity in children and adolescents with CF. The study highlights the influence of CF on autonomic function and suggests HRV measurement as an easy tool to be used in clinical settings as an alternative marker to monitor CF individuals.

Acute hydrogen-rich water ingestion stimulates cardiac autonomic activity in healthy females

Background: Hydrogen-rich water (HRW) has been shown to have a stimulating effect on the human body. Objective: The aim of the study was to assess the influence of acute HRW intake on autonomic cardiac regulation during 50 min of rest sitting. Methods: Fourteen healthy females (age 21.7 ± 1.2 years, body mass 67.8 ± 8.7 kg, height 167 ± 5.5 cm) took part in this double-blind, randomized, placebo-controlled trial with crossover design. Heart rate variability (HRV) was monitored in the sitting position after administration of 1260 ml of HRW or placebo. Time domain indexes of HRV as the square root of the mean of the squares of differences between adjacent RR intervals (RMSSD), the standard deviation of all RR intervals (SDNN) and the ratio of SDNN/RMSSD as an index of sympatho-vagal balance were used to assess autonomic cardiac response. The values were transformed using natural logarithm (Ln). Results: After administration of HRW, we found significantly increased ratio Ln SDNN/RMSSD when comparing it to placebo in 25 min (HRW: 0.40 ± 0.30, placebo: 0.26 ± 0.25, p = .049) and 35 min (HRW: 0.44 ± 0.30, placebo: 0.28 ± 0.28, p = .029) of rest sitting. Ln SDNN was significantly increased after HRW administration when compared to placebo in 45 min (HRW: 4.41 ± 0.42 ms, placebo: 4.28 ± 0.31 ms, p = .049) of rest sitting. Conclusions: Acute HRW ingestion induced a relative increase in sympathetic activity between 25 and 35 min post-ingestion, whereas vagal activity was not affected.

Morning Heart Rate Variability as an Indication of Fatigue Status in Badminton Players during a Training Camp.

This study aimed to clarify whether changes in the fatigue status of elite athletes during a precompetition period could be evaluated using morning heart rate variability (HRV) indices. Eight Japanese National Badminton Team players (age, 23.0 ± 2.8 years) participated in this study. HRV and subjective fatigue were measured during the first (days 1–4: Phase 1) and the second half (days 5–8: Phase 2) of an 8-day national team training camp. The global and parasympathetic HRV indices were as follows: standard deviation of all R-R intervals (SDNN) (Phase 1, 87.5 ms; Phase 2, 104.3 ms; p < 0.05), root mean square of the successive R-R interval differences (RMSSD) (Phase 1, 66.6 ms; Phase 2, 103.6 ms; p < 0.05), and high-frequency component power (HF) (Phase 1, 1412.0 ms2; Phase 2, 3318.5 ms2; p < 0.05). All the aforementioned indices increased significantly from Phase 1 to Phase 2. Significant correlations were observed between the change in subjective fatigue and changes in SDNN, RMSSD, and HF (ρ = −0.80, p = 0.017; ρ = −0.77, p = 0.027; and ρ = −0.80, p = 0.017, respectively). Measuring morning HRV indices may be effective for objectively evaluating changes in the fatigue status of elite athletes during a precompetition period.

Value of heart rate variability on dynamic electrocardiogram in predicting ventricular fibrillation in elderly acute myocardial infarction patients.

Ventricular fibrillation (VF) is the main cause of sudden death in Acute myocardial infarction (AMI) patients. Identifying arrhythmia as early as possible is of great significance in improving prognosis of AMI patients. The article is aimed at exploring the predictive value of heart rate variability (HRV) of dynamic electrocardiogram (DCG) in VF of elderly AMI patients. A total of 122 elderly AMI patients were enrolled as the research objects. They were divided into VF group and simple AMI group (AMI group). All underwent DCG test after admission. The basic data of patients were compared. HRV of DCG was observed. The predictive value of HRV of DCG in VF of elderly AMI patients was evaluated by receiver operating characteristic (ROC) curves. The ratio of Killip at grade II-III, activity of creatine kinase-MB (CK-MB), standard deviation of all R-R intervals (SDNN), the standard deviation of the R-R intervals (SDANN), root-mean-square of the successive differences of normal RR intervals (rMSSD) and percentage of NN50 in the total number of NN intervals PNN50 (PNN50%)]in VF group were higher than those in AMI group (P<0.05). The area under the ROC curves (AUC)and cut-off values of SDNN, SDANN, rMSSD and PNN50% were (0.773, 0.761, 0.800, 0.819) and (135.675, 106.850, 33.570, 14.080), respectively. HRV of DCG is of certain predictive value for VF in the elderly with AMI, which is expected to be an auxiliary diagnosis method of VF.

In newly diagnosed hypertensive children, increased arterial stiffness and reduced heart rate variability were associated with a non-dipping blood pressure pattern

ObjectivesThis study was designed to investigate the differences in pulsatile hemodynamics, echocardiographic findings, 24-h Holter monitoring and heart rate variability parameters of dipper patterns in children with newly diagnosed essential hypertension. MethodsThis study included 30 children with newly diagnosed essential hypertension and 30 healthy controls. The essential hypertension cohort was divided into dippers and non-dippers. Physical examinations, 24-hour ambulatory blood pressure monitoring, 24-h Holter monitoring, 24-h heart rate variability, conventional 2-dimensional and Doppler echocardiography, and tissue Doppler imaging were performed. Pulse wave analysis using an oscillometric monitor was conducted to measure augmentation index (AIx) and pulse wave velocity (PWV). ResultsIn patients with essential hypertension, left ventricular (LV) wall thickness and LV mass index were increased. There were no significant differences in LV mass index and LV wall thickness based on the dipping patterns. Time domain values and the standard deviation of all RR intervals (SDNN) were substantially lower in the essential hypertension group. SDNN values were considerably lower in the non-dipper group compared with the dipper group. In terms of frequency domain measures, low frequency measured in daytime values was much lower in the essential hypertension group compared with the control. The dipper patterns revealed that low frequency measured in nighttime values was also substantially lower in the non-dipper group. Pulse wave analysis and AIx values were notably higher in the essential hypertension patient group and those with non-dipper status. ConclusionSDNN values, which reflect parasympathetic activity, were markedly lower in children with hypertension and the non-dipper group than healthy controls and the dipper group, respectively. Also, parameters related to arterial stiffness, such as PWV and AIx values were significantly higher in children with hypertension and the non-dipper group.

Assessment of Autonomic Nervous System in Children with Celiac Disease: A Heart Rate Variability Study

We evaluated the activity of autonomic nervous system in children with celiac disease by using heart rate variability (HRV) analysis. HRV parameters of 37 children with celiac disease were compared to 36 age- and sex-matched healthy controls. None of the participants had a systemic, central or peripheral neurological disease. Statistically significant differences were present in two parameters; standard deviation of all RR intervals (SDNN) and standard deviation of 5-minute RR interval means (SDANN). Age was negatively correlated with mean, minimum and maximum heart rate. Duration of disease was positively correlated with low frequency power-high frequency power ratio. No correlation was found between anti-tissue transglutaminase IgA level and HRV parameters. Celiac disease may affect autonomic nervous function in children even if there are no symptoms of dysautonomia.

Association between sedentary recreational time and cardiac autonomic modulation in adolescent boys: cross-sectional study

Sedentary behavior has been shown to be an independent risk factor for high blood pressure, obesity, and low physical activity levels in adolescents. However, the association between sedentary recreational behaviors, such as TV viewing and using computer/video games, and cardiac autonomic modulation in adolescents is not well established. Therefore, the aim of this study was to investigate the association between the time spent on sedentary recreational activities and cardiac autonomic modulation in adolescents. This cross-sectional study included 1149 adolescent boys (aged 16.6 ± 1.2 years). Using a questionnaire, we evaluated their sedentary recreational activities and based on the time spent on these activities, the subjects were classified as high (> 2 h/day) or low (≤ 2 h/day) time spent in a sitting position. Heart rate variability (HRV) was used to assess cardiac autonomic modulation. Time (standard-deviation of all RR intervals [SDNN], root mean square of the squared differences between adjacent normal RR intervals [RMSSD], and the percentage of adjacent intervals over 50 ms [PNN50]), as well as the frequency domains (low [LF] and high [HF] frequency) of HRV were obtained. Longer time spent on sedentary recreational activities was found to be significantly associated with low RMSSD (OR = 1.42, 95% CI 1.11; 1.81) and PNN50 (OR = 1.47, 95% CI 1.15; 1.88). associations were maintained even after adjustments for time of day, abdominal obesity, high blood pressure, and physical activity levels. The time spent on sedentary recreational activities was not associated with SDNN (OR = 1.08, 95% CI 0.84; 1.38), HF (OR = 1.31, 95% CI 0.88; 1.94), LF (OR = 1.19, CI 0.94; 1.52), or LF/HF (OR = 1.19, 95% = 0.93; 1.51) (p > 0.05 for all). In conclusion, longer time spent on sedentary recreational activities is associated with poor cardiac autonomic modulation.

Cardiac Autonomic Modulation Is Associated with Arterial Stiffness in Patients with Symptomatic Peripheral Artery Disease

The objective of this study was to analyze the association between cardiac autonomic modulation and arterial stiffness in patients with peripheral artery disease (PAD). This cross-sectional study included one hundred fourteen patients with symptomatic PAD (67.5% men; 65 ± 7 years; body mass index: 26.8 ± 4.5 kg/m2). Heart rate variability (HRV) was measured within time (standard deviation of all RR intervals [beat to beat heart interval] [SDNN], root mean square of the successive differences between adjacent normal RR intervals [RMSSD], and the proportion of successive RR intervals that differed by more than 50msec [pNN50]) and frequency (low frequency [LF] and high frequency [HF]) domains. Arterial stiffness was assessed by carotid-femoral pulse wave velocity (cfPWV). Crude and adjusted linear regression analyses examined the relationship between HRV and cfPWV. Nonsignificant crude associations were identified among cfPWV and RMSSD (P=0.181), SDNN (P=0.105), pNN50 (P=0.087), LF (P=0.376), HF (P=0.175), and LF/HF ratio (P=0.426). After adjustments for age, sex, smoking, body mass index, ankle-brachial index, and use of beta-blockers, significant associations were identified among cfPWV and RMSSD (P=0.037), SDNN (P=0.049), and pNN50 (P=0.049). Cardiac autonomic modulation was significantly associated with arterial stiffness in patients with PAD after adjustment for confounding factors. This relationship may contribute to the enhanced cardiovascular disease risk for PAD patients and provides a target for strategies to improve patient clinical outcomes.

Gender differences in cardiovascular autonomic function status in normal healthy individuals: A cross-sectional study

Background: The autonomic nervous system plays an important role for maintaining vital functions in our body. The balance between sympathetic and parasympathetic systems is essential in maintaining homeostasis. Heart rate variability (HRV) refers to the beat-to-beat variation in heart rate generated by the interplay of sympathetic and parasympathetic nerve activity at the sinus node of the heart. It has been used as a non-invasive tool to analyze the influence of the autonomic nervous system on the heart. The importance of HRV as a tool for assessing the autonomic nervous system activity in many different diseases and conditions has steadily increased. In addition to frequently used long-term HRV analysis, short-term HRV analysis has been increasingly applied due to its suitability for ambulatory care and short-term patient monitoring and due to the almost instant availability of test results. Aims and Objectives: This study aimed at finding out gender differences in cardiac autonomic function tests in normal healthy individuals. Materials and Methods: This cross-sectional study was done on 20 male and 20 female subjects. Ethical committee clearance was taken before the start of the study and written informed consent was obtained from every individual. HRV tests were computed by recording lead II electrocardiogram on RMS polyrite-D machine. It included frequency domain variables such as low-frequency (LF) band, the high-frequency (HF) band, and the LF/HF ratio and time domain parameters such as standard deviation of all RR intervals over the selected time intervals (SDNN) and root mean square of successive differences between adjacent RR intervals (rMSSD). The values were tabulated and statistical analysis was done using unpaired t-test. P < 0.05 was considered statistically significant and

F55. Moderate intensity exercise improves heart rate variability in obese adults with type 2 diabetes

Introduction Obesity, a key risk factor for the development of type 2 diabetes, is associated with dysregulation of autonomic nervous function. Exercise therapy has been shown to improve autonomic nervous system modulation of heart rate variability (HRV) in healthy individuals. Therefore, exercise training may improve cardiac autonomic regulation in a variety of clinical populations including obese adults with type 2 diabetes. Thus, the main aim of this study was to determine the effect of thrice-a-week, six months, moderate aerobic exercise on cardiac autonomic function as measured by HRV in obese adults with type 2 diabetes. Methods 41 obese adults with type 2 diabetes participated in this study. Anthropometric and metabolic parameters were measured, and resting electrocardiogram (ECG) for the HRV analysis at spontaneous respiration was recorded for 5 min in supine position before and after six months of supervised aerobic training given thrice-a-week. Results The mean age, body mass index (BMI), and duration of diabetes of the study population were 44.1 ± 4.5 years, 30.94 ± 1.36 kg/m2, and 16.3 ± 2.7 years, respectively. In time domain variables, standard deviation of all RR intervals (SDNN), the square root of the mean of the sum of the squares of differences between adjacent RR intervals (RMSSD) and percentage of consecutive RR intervals that differ by more than 50 ms (pNN50) were significantly increased after exercise. In frequency domain variables, high frequency (HF) (ms2) and HF (nu) were significantly increased while low frequency (LF) (ms2) and LF/HF ratio were significantly decreased after exercise. But LF (nu) was unaffected after exercise. Conclusion Thrice-a-week, six-month, moderate, supervised aerobic training program in obese adults with type 2 diabetes who were clinically free of cardiovascular disease leads to significant improvements in cardiovascular autonomic function measured by HRV via increasing cardio-vagal tone and decreasing cardio-sympathetic tone.

Low-frequency and low-intensity ultrasound increases cardiac parasympathetic neural activity and decreases clinic hypertension in elderly hypertensive subjects with type 2 diabetes

BackgroundThe aims of the present study were to determine the effects of an ultrasound irradiation on clinic hypertension and the heart rate variability in elderly hypertensive subjects with type 2 diabetes. MethodsWe examined the effects of ultrasound (800 kHz, 25 mW/cm2) applied to the forearm for 10 min on the autonomic nerve activity and the difference between BP at home and at a clinic visit in Japanese subjects with type 2 diabetes and hypertension. ResultsIn 108 subjects who displayed systolic BP (SBP) >140 mm Hg at a clinic visit, 75 subjects (69%) had a mean SBP <135 mm Hg at home and 33 subjects (31%) had a mean SBP >135 mm Hg at home in the morning for 14 days. SBP, pulse rate, and pulse pressure in the ultrasound treatment group were significantly lower than the baseline values in these hypertensive subjects with type 2 diabetes, and lower than those of placebo controls independently of SBP at home. In 31 subjects who displayed systolic BP >140 mm Hg at a clinic, standard deviation of all RR intervals and the root mean square of successive differences were significantly higher in the ultrasound treatment group than the baseline values in these hypertensive subjects with type 2 diabetes, and lower than those of placebo controls. ConclusionsThe ultrasound treatment increases the cardiac parasympathetic neural activity and decreases the differences between SBP at home and at a clinic visit in elderly hypertensive subjects with type 2 diabetes.

The relationship between severity of obstructive sleep apnea and heart rate variability

Background and Objective: Obstructive sleep apnea syndrome (OSAS) is a prevalent disease in adults. Limited evidence regarding the effect of severity of sleep apnea and depression on heart rate variability (HRV) indices exists. Hence, we decided to focus on the association between HRV and severity of OSAS based on depression score. Materials and Methods: A total of 193 patients with confirmed OSAS were selected from a sleep clinic setting. A checklist for demographic data and self-administered questionnaires including the Pittsburgh Sleep Quality Index; Epworth Sleepiness Scale; Beck Depression Inventory; Snoring, Tiredness, Observed apnea, Blood pressure, Body mass index, Age, Neck circumference (STOP-BANG), and Gender questionnaire were filled in. We used two domains of HRV (e.g., frequency and time) estimation. Results: The mean number of pairs of adjacent RR intervals (time between QRS complexes) differing by more than 50 ms in the entire analysis interval (NN50 count) was significantly different among various severity OSAS groups (μ = 2639.12 ± 478.98 for mild and moderate, and 2313.81 ± 670.54 in severe OSAS; P = 0.0200). In frequency do-main, the indices were higher in severe OSAS patients. Statistically significant association was between HRV parame-ters (standard deviation of all RR intervals, mean of the standard deviation of all RR intervals for all 5-minutes segments, NN50 count, the NN50 count divided by the total number of all RR intervals, average total power, low frequency power) and OSAS severity. Conclusion: There are some statistically significant differences between OSAS severity and parameters of HRV.